I'm not saying that's wrong and I'm not giving spiritual advice, but keep in mind fasting foods of 200, 1000, 2000 years ago were much more nutrient rich than those same foods are today. For example, wheat. Not only is the average wheat berry less nutritious (because fields are flooded with fertilizer devoid of micronutrients), they strip some of the better parts of it for longer shelf life when making flour, so our bread is less healthy.
St Paisios said a similar thing (and honestly gave revolutionary advice, as his early protests against GMO mass produced food came out decades before “nutritional scientists” picked it up). Now I must ask my priest about this.